The use of robotic devices to perform physical tasks has increased in recent years. Mobile robotic devices can be used to perform a variety of different tasks. These mobile devices may operate in semi-autonomous or fully autonomous modes. Some robotic devices are constrained to operate in a contained area, using different methods to obtain coverage within the contained area. These robotic devices typically have an integrated, fixed positioning and navigation system. Mobile robotic devices often rely on dead reckoning or use of a global positioning system to achieve area coverage. These systems tend to be inefficient and are often cost-prohibitive.
Mobile robotic devices often rely on visual landmarks for localization and navigation. Visual landmarks may not be present in certain areas of a worksite or in some worksites at all, such as large, open fields, for example. A worksite may be any area or location where robotic devices are used to perform physical tasks. Other visual landmarks that may be present, such as natural landmarks, for example, may have ambiguity and seasonal occlusion from vegetative growth during certain times or seasons.
Physical perimeters, such as fences or electronic boundaries of buried wire carrying a signal detectable by a robotic device, may also be used for localization and navigation. However, physical perimeters present a challenge in some situations. One example is when a sidewalk or driveway must be traversed to access a worksite.